In an allogeneic (A-loh-jeh-NAY-ik) transplant, we take healthy stem cells and give them to another person. The stem cells grow and mature into new, healthy stem cells that replace the patient’s cancerous cells.
The new cells come from a donor or from donated umbilical cord blood. If they’re from a donor, their stem cells are harvested and then donated (given) to the person having the transplant.
Before your transplant, you will have chemotherapy or a combination of chemotherapy and radiation therapy. This therapy kills the cancer cells, stops your immune system from working as it normally does, or both.
We then add new stem cells to your bloodstream through a tube. The procedure is like a blood transfusion.
Read our guide to allogeneic stem cell transplants. It helps you and your caregivers understand what to expect throughout your transplant journey.
Types of Allogeneic Transplantation
Unmodified Stem Cell Transplant
This is a conventional stem cell transplant. We transplant the stem cells without first changing them in a laboratory. The transplanted cells include T cells, a type of immune cell. T cells are white blood cells that will play an important role in your new immune system.
Unmodified transplants are better for people who are at risk for relapse (their disease comes back). They’re also better for people who can take medications that prevent a complication called graft-versus-host disease (GVHD). This is when the donor’s T cells start to attack and harm your body’s organs.
In a laboratory, we remove T cells (immune cells) from the donated stem cells. This is to prevent graft-versus-host disease (GVHD), where the donor’s T cells start to attack and harm your body’s organs. T cell-depleted transplants have a lower risk of GVHD, so you don’t need medications to prevent GVHD.
After we remove the T cells, we transplant the rest of the donated cells, including blood-forming stem cells. You will form new T cells from the donor’s stem cells. They’re less likely to cause GVHD.
Cord Blood Transplants
In a cord blood transplant, the stem cells come from the umbilical cord and placenta of a healthy newborn. It’s not as important for the newborn donor and the patient to have a very close tissue type match. That’s because there’s only a low chance of graft-versus-host disease (GVHD) after a cord blood transplant. GVHD is when the donor’s T cells (immune cells) start to attack and harm your body’s organs.
Cord blood transplants can be a good choice for people who don’t have a matched donor. They’re a good option for people who need conventional transplants. Learn more about MSK’s research on cord blood transplantation.
Donor Lymphocyte Infusions (DLI)
This transplant is for people who have certain kinds of cancer that come back after a stem cell transplant. Your doctors may slowly give you more T cells (immune cells) from the original donor. The low levels of T cells can stop the cancer. It does not cause much graft-versus-host disease (GVHD), where the donor’s T cells start to attack and harm your body’s organs.
Finding a Donor
If you need an allogeneic transplant, finding the right donor is an important step.
The immune system can tell the difference between your body’s own cells and foreign cells. It tries to destroy the foreign cells, so your donor’s tissue type should closely match yours.
If the donor is not a close match, your immune system can react badly to the transplant. This causes complications that can be serious and hard to treat.
The test to find the best allogeneic transplant donor looks at your human leukocyte (LOO-koh-site) antigens (HLA). These are markers on the surface of your white blood cells. Often the best donor is someone related to you by blood who has the same HLA genes as you. But only about 1 out of every 4 people has this ideal donor.
For everyone else, doctors check other family members related to you by blood. They may only be a partial HLA match, also called a haplo match. Doctors also check volunteer donor registries. In some cases, we can use umbilical cord blood stored in public banks for allogeneic transplantation.
The National Marrow Donor Program has a list of possible stem cell donors. It’s also linked to other national and international registries. Together, there are almost 40 million potential donors.
If there’s no matching donor in your family, you can use your HLA type to search for potential unrelated donors. You can also search for cord blood units from the National Cord Blood Program. There is also data on donors and cord blood units.
Learn about donating bone marrow and blood stem cells.
You may find some potential matches through online searches. Only a transplant center, however, can tell if they’re a good match and available.
MSK has a team of search coordinators who look for an unrelated adult volunteer donor or umbilical cord blood units. If you choose MSK as your transplant center, we will help look through the matches. For more information, please call 212-639-7431.
Harvesting the Donor’s Stem Cells
Bone marrow harvesting is a procedure that takes place before your transplant. Doctors will harvest (collect) the blood-forming stem cells from your donor’s bone marrow or blood.
Bone Marrow Donation
Bone marrow is collected from harvest sites that have a lot of marrow. These often are the front and back of the hips. The breastbone has a lot of marrow, but we very rarely collect from there. The most common harvest site is the back of the hips.
Bone marrow is collected during an operation. During a bone marrow harvest, the donor has general anesthesia (medication to make you sleep). A doctor puts a hollow needle into the harvest site. There are no stitches, just some pain and tenderness at the harvest site for about a week.
Stem Cell Donation
We also collect stem cells from a donor’s circulating blood. These are called peripheral blood stem cells. They’re collected from the donor’s bloodstream using a procedure called apheresis (a-feh-REE-sis).
The first step is to increase the amount of stem cells in the donor’s bloodstream. They will get injections (shots) of medication that causes their body to make more stem cells than usual. They can cause flu-like symptoms and bone pain for a few days.
A few days before the procedure, donors often are given either:
- G-CSF (filgrastim, Granix®, Neupogen®, Zarxio®)
- GM-CSF (sargramostim, Leukine®)
- A combination of both.
Apheresis does not need to be done in an operating room. The stem cells are easily collected while the donor is awake. The donor does not need general anesthesia (medication to make you sleep).
Apheresis takes place for several hours over 2 to 4 days. The donor’s blood comes out through a tube placed in their vein. It then goes through a machine that separates the stem cells from other blood cells. Those other blood cells are returned to the donor. The collected stem cells are either used right away, or they’re frozen and stored.